<!DOCTYPE html>
<html>
<head>
	<title></title>
	
</head>
<body>
	<div id="container">
		<div>11111</div>
		<div>22222</div>
		<p>ppppp</p>
		<span>span</span>
	</div>
	<div>hello</div>
	<div id="main">world</div>
	<div>heima</div>
	<script type="text/javascript">
		var container = document.getElementById('container');
		var divs = container.getElementsByTagName('div');
        console.log(divs)
        var first_div = document.querySelector('#container div:first-child')
        console.log(first_div)
        divs = document.querySelectorAll('#container div')
		console.log(divs)
	</script>
</body>
</html>